Reinforced geocell and a method for producing the same

ABSTRACT

A reinforced geocell is made of flexible polymeric strips arranged in rows and interconnected in a staggered order lengthwise to form a three-dimensional cell structure when stretched in the direction normal to surfaces of the strips. The strips are provided with drainage apertures and are reinforced in a longitudinal direction with reinforcing threads having at least two fibrous elements twisted along full lengths thereof. A method for producing a geocell includes extruding a polymeric material for producing a sheet material, laying out twisted reinforcing threads onto the sheet material, calendaring the sheet material when heated to 120 to 200° C. to press reinforcing threads into the sheet material, cutting a reinforced sheet material into sheets, perforating the sheets for producing drainage apertures, cutting the sheets into strips, and interconnecting the strips in a staggered order to form a three-dimensional cell structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

See Application Data Sheet.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

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INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR ASA TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

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STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINTINVENTOR

Not applicable.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to the construction industry, in particular to ageocell and a method for producing the same. The invention may be usedin the oil-and-gas, transport and hydraulic engineering industries forreinforcing structural units and pitching weak bases of industrial andcivil structures as well as shoreline slopes and water body channels.

2. Description of Related Art Including Information Disclosed Under 37CFR 1.97 and 37 CFR 1.98

The closest analogue to the present invention is a reinforced geocelldisclosed in Patent RU 2459040, Aug. 20, 2012. The geocell is formedfrom flexible high-density polyethylene (HDPE) strips arranged inseveral rows and interconnected in a staggered order along lengths ofthe strip, in order to form a cell structure when the strips arestretched in a direction normal to surfaces thereof. The strips areprovided with drainage apertures having the shape of elongatedrectangles with semicircles on short sides of the strips, and the stripsare reinforced lengthwise with aramid or carbon reinforcing threads at aratio, in wt. %, of aramid or carbon thread to HDPE of 0.3 to 3. Saidstructure is disadvantageous in that reinforcing threads may slide offthe geocell web if shear stresses appear which leads to a reduction instrength of the geocell.

BRIEF SUMMARY OF THE INVENTION

The objective of the claimed group of inventions is to eliminatedrawbacks of the closest analogue.

The technical effect of the invention is improved reliability of holdingreinforcing elements in geocell strips as well as improved tensilestrength of a geocell at stretch and shear loads.

This technical effect is achieved due to that a reinforced geocell ismade of flexible polymeric strips arranged in rows and interconnected ina staggered order lengthwise to form a three-dimensional cell structurewhen stretching in the direction normal to surfaces of the strips, thestrips provided with drainage apertures as well as reinforced byreinforcing threads in a longitudinal direction, wherein saidreinforcing threads consist of at least two fibrous elements twistedalong the whole length thereof.

Also, the technical effect is achieved in a method for producing areinforced geocell, comprising: extruding a melted polymeric materialfor producing a sheet material, laying reinforcing threads onto thesheet material, calendering the sheet material with heating to atemperature ranging from 120 to 200° C. for the purpose of ensuringpressing said reinforcing threads into the sheet material, cutting areinforced sheet material into sheets, perforating said sheets forproducing drainage apertures, cutting said sheets into strips, andconnecting the strips in staggered order to form a three-dimensionalcell structure, said reinforcing threads consisting of at least twofibrous elements twisted along the whole length thereof.

Other embodiments of the invention are possible, where:

-   -   the reinforcing threads have 5 to 20 twists per centimeter;    -   the reinforcing threads are made of polyester or lavsan;    -   the reinforcing threads have thickness not more than 1 mm and        are arranged with a transverse pitch ranging from 1 to 10 mm;    -   the strips are made from HDPE or a mixture of HDPE and        low-density polyethylene (LDPE);    -   the drainage apertures have a shape of elongated rectangles with        rounded corners;    -   when implementing the method, the reinforcing threads are        impregnated with an adhesive composition before laying onto the        sheet material;    -   when implementing the method, the sheet material is calendered        for ensuring pressing the reinforcing threads to a depth at        least 0.25 mm.

As distinct from known solutions, reinforcing elements in the form ofthe twisted reinforcing threads consisting of two or more fibrouselements are used in the claimed geocell. This configuration of thereinforcing threads ensures reliable holding thereof in the strips (orribbons) of the geocell. Furthermore, it is found that the use of thetwisted threads ensures improved tensile strength of the geocell atstretch and shear loads that cause bends of the strips of the geocelland the reinforcing elements themselves, thus, consequently, enabling toimprove indentation resistance of a base (soil) reinforced by such thegeocell.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is illustrated by the accompanying drawings.

FIG. 1 shows a structure of the strips used for producing the geocell.

FIG. 2 shows a view of the reinforcing threads.

FIG. 3 shows a view of the geocell, according to the claimed invention.

DETAILED DESCRIPTION OF THE INVENTION

The gas The claimed reinforced geocell (FIG. 3) consists of flexiblestrips (1) made of a sheet material (FIG. 1), which flexible strips (1)are arranged in rows and interconnected in a staggered order (seams (2))by, e.g., ultrasonic welding or threads.

The strips (1) are made of a polymeric material, in particular, of HDPEor a mixture of HDPE and LDPE. The strips (1) may have a thickness of 1to 2 mm.

Further, the strips (1) are reinforced lengthwise with reinforcingthreads (3) comprising two or more fibrous elements (fibers) twistedalong a full length thereof (FIG. 2). Preferably, the fibrous elementshave 5 to 20 twists per 1 centimeter of the lengths thereof. Thereinforcing threads (3) may be made of polyester or lavsan and have adiameter up to 1 mm, and the reinforcing threads are pressed into thestrip (1) to a depth at least 0.25 mm and arranged with a transversepitch ranging from 1 to 10 mm.

The strips (1) are also provided with drainage apertures (4) havingpreferably the shape of elongated rectangles with rounded corners.

The disclosed geocell may be produced as follows.

A melted polymeric material is extruded for producing a polymeric sheetmaterial. The twisted reinforcing threads are laid onto the sheetmaterial produced, and the latter is calendered at a temperature rangingfrom 120 to 200° C. by using embossed rolls that ensure pressing thereinforcing threads to a depth at least 0.25 mm. In order to improveadhesion, the reinforcing threads may be preliminarily impregnated withan adhesive composition, e.g., with Latacril BM glue (TU (stands fortechnical regulations) 2385-403-00208947). A reinforced sheet materialthus produced is roll-cooled and cut into sheets. Then, the sheets areperforated for producing drainage apertures. After that, the so producedperforated sheets are cut into strips (ribbons). The strips areinterconnected in a staggered order by using ultrasonic welding and aresewn together with a thread, thus forming a three-dimensional cellstructure. The final structure is stretched for producing a geocell.

Example

According to the above disclosed method, a geocell was produced frompolyethylene strips having a thickness of 1.5 mm and reinforced withtwisted polyester threads having a thickness of 1 mm and consisted oftwo fibrous elements (threads) having a thickness of 0.5 mm each and 10twists per cm. The threads were arranged with a transverse pitch of 2mm. Also, the strips were provided with 20×4 mm rectangular drainageapertures with rounded ends.

For the purpose of comparison, a geocell was produced according to theclosest analogue under the same parameters but with the use ofnon-twisted reinforcing threads.

The results of comparison between the disclosed structure and that knownfrom the closest analogue are shown in Table 1.

TABLE 1 Characteristics of geocells produced according to the closestanalogue and the claimed invention Geocell produced according to theclosest analogous Claimed Parameter solution geocell Thickness of thestrip, mm 1.5 1.5 Tensile strength of the non-perforated strip 20.2525.22 at a maximum load, kN/m Tensile strength of the perforated stripat a 16.1 17.47 maximum load, kN/m Unit elongation of the perforatedstrip at a 22.45 21.05 maximum load, % Unit elongation of thenon-perforated strip 100.42 101.33 at a break point, % Seam pullstrength of the perforated strip, 18.66 19.07 kN/m Strength of aninfilled compacted material 2.1 2.4 reinforced by the geocell at shearloads, kg/cm²

Thus, the claimed structure ensures reliable holding of the reinforcingelements in the geocell strips as well as improved strength of thegeocell at stretching and shear loads.

1. A reinforced geocell, comprising: flexible polymeric strips arrangedin rows and interconnected in a staggered order lengthwise to form athree-dimensional cell structure when being stretched in a directionnormal to surfaces of said strips, the strips provided with drainageapertures and reinforced with reinforcing threads along a longitudinaldirection of said strips, wherein the reinforcing threads are comprisedof at least two fibrous elements twisted along lengths thereof.
 2. Thegeocell, according to claim 1, wherein the reinforcing threads have 5 to20 twists per cm.
 3. The geocell, according to claim 1, wherein thereinforcing threads are comprised of at one of a group consisting ofpolyester and lavsan.
 4. The geocell, according to claim 1, wherein thereinforcing threads have thickness of not more than 1 mm and arearranged with a transverse pitch ranging from 1 to 10 mm.
 5. Thegeocell, according to claim 1, wherein the strips are comprised of atleast one of a group consisting of HDPE and a mixture of HDPE and LDPE.6. The geocell, according to claim 1, wherein the drainage apertureshave a shape of elongated rectangles with rounded corners.
 7. A methodfor producing a reinforced geocell, comprising the steps of: extruding amelted polymeric material for producing a sheet material, layingreinforcing threads onto the sheet material, calendering the sheetmaterial heated to 120 to 200° C. for ensuring pressing the reinforcingthreads into the sheet material, cutting a reinforced sheet materialinto sheets, perforating the sheets for producing drainage apertures,cutting the sheets into strips, and connecting the strips in a staggeredorder to form a three-dimensional cell structure, wherein thereinforcing threads are comprised of at least two fibrous elementstwisted along lengths thereof.
 8. The method, according to claim 7,wherein the reinforcing threads are impregnated with an adhesivecomposition before the step of laying onto the sheet material.
 9. Themethod, according to claim 7, wherein the reinforcing threads arecomprised of at least one of a group consisting of: polyester andlavsan.
 10. The method, according to claim 7, wherein the sheet materialis calendered for ensuring pressing of the reinforcing threads to adepth at least 0.25 mm.